set data "http://iridl.ldeo.columbia.edu/SOURCES/.NOAA/.NCEP/.EMC/.CMB/.GLOBAL/.Reyn_SmithOIv1/.monthly/.sst/T/%28Dec%201989%29%28Nov%201999%29RANGE/Y+partial/%5BX+%5Ddetrend-bfl/T+differences/Y+differences/dods"

When you give that url to a DODS client, it actually sends a url with one of the
following six file extensions: .das, .dds, .dods, .info, .ver or .help.
The extensions tell the DODS server which object to return (see table).

Note: Many DODS clients supply these extensions for you so you don't
need to append them (for example when using interfaces supplied by DODS or
software re-linked with a DODS client-library). Generally, you only need to
add these extensions if you are typing a URL directly into a WWW browser.

*On GrADS startup, the config line should read
Config: ... DODS-enabled ...,
otherwise DODS is not installed and giving GrADS a URL will result in a
file-not-found error.